Rotary screen tensioner for single sided drive

ABSTRACT

A rotary screen printing machine has a web to be printed upon while advancing from one end of the machine to the other. A plurality of cylindrical uninterrupted or seamless screens extend transversely of the direction of travel of the web and have relatively rigid hollow sleeves connected to the opposite ends thereof. Only one of the sleeves of each screen is driven, and means is provided for maintaining the screens under tension axially thereof while being driven. The screens may be mounted in two groups offset with respect to one another transversely of the direction of travel of the web. The doctor blade assembly within each screen can be mounted and dismounted through the sleeves mounted at opposite ends of the associated screen.

'United States Patent Van der Winden ROTARY SCREEN TENSIONER FOR SINGLESIDED DRIVE [75] Inventor: Johannes Bernardus Van der Winden,Amstelveen, Netherlands [73] Assignee: Konishiroku Photo Industry Co.,

Ltd., Tokyo, Japan [22] Filed: Sept. 5, 1973 [21] Appl. No.: 394,645

Related U.S. Application Data [63] Continuation-in-part of Ser. No.108,394, Jan. 21, I971, abandoned, which is a continuation of Ser. No.608,438, Jan. 10, 1967, abandoned.

(30] Foreign Application Priority Data Feb. 4, 1966 Netherlands 6601488[52] U.S. Cl. 101/116; l0l/l27.l; lOl/128.l [51] Int. Cl. B41F 15/38[58] Field of Search 101/l27.1,128.1, 127, 101/115, 116, 119,120, 126

[56] References Cited UNITED STATES PATENTS 627,311 6/1899 Spalckhaver101/249 X 1,784,037 12/1930 Wolf 101/152 [451 July 1, 1975 3,565,0022/1971 Bohm 101/116 3,572,240 3/1971 Bohm 101/116 3,585,930 6/1971 Bohm101/116 3,675,571 7/1972 Vertegaal.... 101/116 X 3,718,086 2/1973Vertegaal 101/120 X Primary ExaminerEdgar S. Burr Assistant ExaminerR.E. Suter Attorney, Agent, or Firm-Bierman & Bierman 5 7 ABSTRACT Arotary screen printing machine has a web to be printed upon whileadvancing from one end of the machine to the other. A plurality ofcylindrical uninterrupted or seamless screens extend transversely of thedirection of travel of the web and have relatively rigid hollow sleevesconnected to the opposite ends thereof. Only one of the sleeves of eachscreen is driven, and means is provided for maintaining the screensunder tension axially thereof while being driven. The screens may bemounted in two groups offset with respect to one another transversely ofthe direction of travel of the web. The doctor blade assembly withineach screen can be mounted and dismounted through the sleeves mounted atopposite ends of the associated screen.

16 Claims, 7 Drawing Figures AW-"7551,JIJ! w m: 53,892,176 sum 1 INVENTOR.

JdHANNES B. AN DER wiNDEN SHEEI INVENTOR. VAN DER wiNoEN J'OHANNES Bva-27s,

SHEET INVENTOR. JOHANNES a. VAN DER wmoau aui} 197? c'agz'lvrs SHEET 5 Aa: 7. INVE-IZTOR JOHANNES B. l44N DER W/NDEN ATTORNEY 1 ROTARY SCREENTENSIONER FOR SINGLE SIDED DRIVE RELATED APPLICATIONS The presentapplication is a continuation-in-part of US. Pat. application Ser. No.108 394, filed Jan. 21, 1971, now abandoned and the latter applicationwas a continuation of US. Pat. application Ser. No. 608,438 filed Jan.10, I967, and abandoned.

The present invention relates to a rotary screen printing machinewherein a rotating screen is employed for printing on a web in contacttherewith. These screens extend transversely of the direction of travelof the web and are connected with relatively rigid members at theopposite ends thereof. In the prior art, when employing uninterruptedscreens which are disposed in continuous printing contact with theassociated web, this type of screen is always driven from both endsthereof since the screens are not sufficiently rigid to withstand thetorsional stresses of a single end drive.

On the other hand, when it is desired in the prior art to provide asingle end drive, screens of a different construction have been employedincluding a rigid framework or other type of reinforcing constructionwhich requires periodic and cyclic lifting of the screen out of printingrelationship with the web.

In addition, the construction of prior art machines of this type is suchthat it is relatively difficult and time consuming procedure to mountand dismount the doctor blade assemblies with respect to the screens andto change the screens when required.

It is therefore an object of the present invention to provide a rotaryscreen printing machine having a plurality of cylindrical perforatedscreens wherein each screen, which is normally incapable of transmittingtorsional forces, can be driven from one end while the other end isfreely journalled.

In the present invention, means is provided for advancing a web to beprinted from one end of the machine to the other. A plurality ofcylindrical seamless or uninterrupted screens extend transversely of thedirection of travel of the web and relatively rigid hollow sleeves areconnected to opposite ends of each of the screens. Bearing means supportthe sleeves and the screens for rotation so that the screens bear incontinuous printing relation upon the web and it is not neces sary toperiodically lift the screens away from the printing web.

The screens are continuously driven by driving the sleeve at only oneend of each of the screens while the sleeve at the opposite end of eachof the screens is freely rotatable. Means is provided for maintainingthe screens under tension axially thereof while being driven whereby thesleeve at the opposite freely rotatable end of each screen is rotated bya driving torque transmitted solely through the associated screen. Inthis manner, a cylindrical seamless screen may be driven from only oneend thereof.

A doctor blade assembly is supported within each of the screens andincludes a support member extending beyond the sleeves at opposite endsof the associated screen. The sleeves are of such a size relative to thedoctor blade assembly that the doctor blade assembly can be mounted anddismounted with respect to the screen through the ends of the sleevesconnected to the screen. There are no members or elements within thescreen either for tensioning or supporting the screen so that after thedoctor blade assembly is removed the screen is entirely empty and can beeasily dismounted for changing screens thereby reducing any downtimeperiods.

The bearing means for supporting each of the screens comprises a pair ofaligned bearing assemblies, one of which is freely rotatable and theother one of which receives the drive for the associated screen. Thedrive is transmitted from the driven bearing assembly solely through theuninterrupted screen to the opposite freely rotatable or non-drivenbearing assembly. This enables the screens to be divided into aplurality of groups wherein each group can receive its own drive.

Two or more groups of screens may have different diameters and eachgroup can be driven at its own particular speed in such a way that thecircumferential speed in the printing area of all the screens will besubstantially identical.

The construction of the present invention also enables the screens to beso arranged that the screens of one group may alternate with the screensof another group with the screens of one group being driven from one endthereof and the screens of the other group being driven from theopposite end thereof.

The means for maintaining the screens under tension axially thereof inorder to enable a drive from only one end of the screens also providesadditional functions such as adjustment of each screen transversely ofthe direction of movement of the web and further enables at least oneend of each screen to be adjusted longitudinally of the direction oftravel of the web so that the screen is positioned substantiallyperpendicular to the direction of travel of the web.

Due to the fact that the screens are driven from only one end thereof,the length of the screens is limited. The screens may be divided intotwo groups which are offset with respect to one another transversely ofthe direction of travel of the web so that the screens are adapted toprint a web having a width twice as great as the effective length ofeach screen. When the two groups of screens are employed, an additionalamount of work is involved in replacing the various screens, andaccordingly the construction which permits the screens to be morereadily replaced is an important feature of the present invention.

Other objects and advantages of the invention will be apparent uponreference to the accompanying description when taken in conjunction withthe following drawings, which are exemplary, wherein;

FIG. I is a top perspective view partly broken away of a firstembodiment of the invention;

FIG. 2 is a longitudinal section through one of the screens and theassociated supporting structure shown in FIG. 1',

FIG. 3 is a section through a portion of the structure shown in FIG. 2illustrating the tensioning means of the machine;

FIG. 4 is a sectional view on an enlarged scale taken substantiallyalong line lVlV of FIG. 2 looking in the direction of the arrows;

FIG. 5 is a top perspective view of a modified form of the invention;

FIG. 6 is a schematic view of a web printed by a machine as shown inFIGS. 1-4 inclusive; and,

FIG. 7 is a schematic vieiitg of a Web printed by a ma chine as shown inFIG. 5 of the tli'awings.

Referring now to the drawings wherein like reference symbols designatecorresponding parts throughout the several views, the machine as shownin FIGS. 1-4 includes a frame I supporting a plurality of bearing meansfor a series of screens or stencils 3. Each bearing means comprises apair of spaced aligned bearing as semblies 4 and S in which the oppositeends of a corresponding cylindrical screen are supported. The machinefurther comprises means for supporting, guiding and advancing the web ofmaterial 35 to be printed upon. This portion of the machine of thepresent invention is of conventional construction as, for example,disclosed in U.S. Pat. Nos. 3,29l,044; 3,304,860; 3,313,232; 3,420,167;and in US. Patent application Ser. No. 17,136 now abandoned which is acontinuation application of US. Patent application Ser. No. 395,764, nowabandoned.

However, in the present invention, each screen as supported in itsbearing assemblies 4 and is driven from only one end of the screen. Inthe drawings, drive means is associated with each bearing assembly 4whereas each screen 3 is supported for free rotation at each bearingassembly 5.

Each bearing assembly 4 includes a casing 6 within which are disposedthree spaced supporting rollers 7. Each bearing assembly 5 includes acasing 6' within which are disposed three spaced supporting rollers 7'.A sleeve 8 is rotatably supported by rollers 7 and a sleeve 8' isrotatably supported by rollers 7' such that both sleeves 8 and 8 areaxially movable thereon. Each screen 3 comprises a cylindrical seamlessscreen as disclosed in the aforesaid patents and patent applicationwhich is normally incapable of withstanding any substantial torsionalloading. Such screens are generally made of pure nickel and the wall isvery thin, generally of the order of 008-0. 1 9 mm. The cylinder isregularly perforated over its entire surface and is therefore incapableof withstanding the torsional stresses of being driven from one endthereof.

The opposite ends of each of screens 3 are provided with known couplingor adaptor rings 27 which are connected at 26 to sleeves 8 and 8respectively to permit rapid mounting and removing of the screens. Thesleeves as well as the coupling rings are formed of a suitablerelatively rigid substance such as metal so as to be able to impartdriving torque to the screens which normally would be incapable oftransmitting drive therethrough. Both the sleeves and the coupling ringsare hollow and of a suitable dimension for a purpose hereinafterdescribed.

A hollow cylinder of a thin and flexible material such as the perforatedscreens of the present invention, will become shortened in length whensubjected to torsional forces. The application of torsional forces willcause a twisting of the cylinder so that creases and buckles will occurtherein and the length of the cylinder will decrease. Since it isnecessary during printing that the screen be as rigid as possible, it isdesirable to maintain the screen in its cylindrical form as near aspossible. In order to maintain the original length and form of thecylindrical screen even when subjected to torsional forces an axialforce is applied to the screen so as to place the screen under tensilestress. Therefore, the application of axial force will maintain thelength of the screen constant under the influence of torsion and thescreen can be driven from one end. The amount of tensile stress whichmust be applied to such a cylindrical screen can be calculated throughknown mathematical procedures.

In an actual test, an 80 mesh cylindrical screen having a wall thicknessof about 0.0003 inches was sub- 5 jected to torsional forces both undertension and without any tension. The screen with tension withstood atorque of 9.5 foot-pounds before buckling at a deflection of 0.008inches, while the cylinder without tension could withstand only 6.5foot-pounds before deflecting the same amount and buckling. Thedeflection is measured at the end of the cylinder and indicates theamount that one end of a longitudinal line drawn on the surface of thecylinder deflects from its original position.

As seen in FIG. 2, each of sleeves 8 is provided with a gear 9 having apitch diameter corresponding to the diameter of the associated screen 3.It will be appreciated that screens of different diameters may beemployed as illustrated in phantom lines in Flg. 4. Different sizes ofenclosure casings 6 with correspondingly sized sleeves 8 are thus usedfor different sizes of screens and different sizes of stencils can beused. Conventionally, five different sizes are available.

The main drive wheel I2 for each screen is in mesh with gear 11 of thegear train 10, II which, similar to gear 12, is rotatably supported byframe 1. Gear 9 is in mesh with gear 10 whereby each screen is driven atone end thereof from an associated main drive gear 12.

As seen in FIG. 1, the first screen on the right side of the figure isdriven at its near end while the next screen is driven at its far end.This alternating arrangement is continued from right to left in thefigure so as to provide two groups of alternate screens which are drivenfrom opposite sides of the machine. Each bearing assembly 4 is at thedriven end of the screen while each bearing assembly 5 is at the freelyrotating or nondriven end of the associated screen. For adjustmentpurposes, the two gears 10 and I] of the gear train are mounted so as toallow for slight relative angular displacement or adjustmenttherebetween as known in the art.

Referring to FIGS. 1, 3 and 4, tensioning means for each screen isindicated generally at 13 and includes a pair of rods 14 disposeddiametrically opposite to one another with respect to the center line 15of bearing assemblies 4 and 5 as seen in FIGS. 2 and 4 and when three ormore rods 14 are used they are spaced equal arc distances from eachother on a generatrix of a cylinder concentric to center line 15. Eachof rods 14 has operatively associated therewith a sleeve 17, a sleeve19, a resilient member 16, and eccentric mounting bushing 22 and atension cam 20. Each sleeve 17 has a hand wheel portion 24 and isprovided with a circumferential groove by means of which it is rotatablysupported in the frame 1 but held against axial movement with respectthereto. The end 18 of the associated rod 14 is threadedly engaged withthe sleeve 17 so that when the latter is rotated in the frame the rod isshifted axially with respect to the frame.

The end 18 of the rod 14 also has a shoulder 18 spaced therefrom forengaging casing assembly 6 so that when hand wheel 24 is rotated toshift the rod 14 axially to the left in FIG. 3, casing assemblies 6 and6' are likewise so shifted. A thrust bearing 25 is interposed betweencasing 6 and a shoulder 45 formed on sleeve 8. Accordingly, when casing6 is shifted to the left, sleeve 8 and the screen secured theretotogether with casing 6' and sleeve 8' are also shifted to the left. Thispermits transverse adjustment of the screen with respect to the web.

At the opposite end of each rod 14, a sleeve 19 is slidably mounted onrod 14. The sleeve 19 has mounted therein a cam having an eccentric 40pivotable around axis 41 and provided with an operating handle 21. Aresilient member or compression spring 16 is disposed between a shoulderon the sleeve 19 and easing assembly 6'. Sleeve 19 may be shifted to theright as seen in FIG. 3 by manipulating cam 20 to the position shown inFIG. 3. The cam reacts against the fixed end face of rod 14 and thusshifts the sleeve 19 to the right.

When the sleeve 19 is shifted to the right, spring 16 is compressed andexerts a greater force against casing assembly 6 which, in turn, exertsa force to the right against an axial thrust bearing disposed betweencasing assembly 6' and a shoulder formed on sleeve 8'. Accordingly,applying a greater axial force on casing assembly 6' to the right urgesthe associated end of the screen to the right to effect the desiredaxial tensioning of the screen.

An eccentric bushing 22 is fixed axially with respect to the frame I butis rotatable relative thereto. This bushing supports sleeve 19 within abore thereof so that rotation of the bushing by means of handle 23allows sleeve 19 and casing 6' to be shifted longitudinally with respectto the direction of travel of the web. in this manner, one end of thescreen may be shifted longitudinally so as to enable each screen to beproperly positioned in the transverse direction and to be aligned sothat its axis is exactly perpendicular to the direction of travel of theweb being printed.

Casing 6 and 6' of the two bearing assemblies 4 and 5 for each screenrest upon the machine frame with the stencil tensioning means fixingthese casings in place both longitudinally and transversely with respectto the frame. Each casing 6 because of threaded sleeve 17 cannot shiftlongitudinally with respect to the direction of travel of the web.However, rotation of threaded member 17 by means of knob 24 shifts rod14 together with the two casings 6 and 6' secured thereon transverselywith respect to the direction of travel of the web. The screen 3 carriedby these casings is also displaced so that each screen can thus beprecisely positioned in the direction transverse to the web.

As a result, both casings 6 and 6' may be shifted transversely whilecasing 6 at the non-driven end of each screen may also be shiftedlongitudinally.

The tension adjustment for each screen is effected by moving casing 6toward or away from casing 6. As shown in F IG. 3, manipulation ofhandle 21 causes cam element 40 to rotate about axis 41 and shiftssleeve 19 axially on shaft l4. Spring 16 is thereby compressed orrelaxed. as the case may be, to thereby modify the tension on screen 3.Tensioning and proper positioning of the screens may accordingly beeasily and quickly effected.

Disposed within each screen 3 and the associated sleeves 8 and 8' is adoctor assembly 28. The doctor assembly comprises a supporting member 29of tubular construction having a longitudinally extending boretherewithin, and doctor blade 30 is supported by this supporting member.Supporting member 29 has a tapered finder nose 3] at one end thereofcooperating with a support including an upwardly slanting supportingface 32. The doctor blade assembly is inserted upside down into thescreen through sleeve 8 and moved until the finder nose runs up alongsurface 32. When the doctor blade assembly is in the final position, itis rotated a half turn and secured against displacement by means of afastening member 33 of known type such as a threaded clamp which engagesthe supporting member 29.

The doctor blade assembly and the internal diameter of sleeves 8 and 8'are of such dimension that the doctor blade assembly can be readilymounted and dismounted with respect to the screen through the sleeves atopposite ends of the screen.

Printing liquid is supplied through a tube 34 to the longitudinallyextending bore provided within supporting member 29. As seen in FIG. 4,the printing liquid is adapted to flow downwardly as shown in dottedlines through suitable outlets provided in supporting member 29 into theinterior of the screen and rearwardly of the doctor blade 30.

Both the driving and the tensioning members are arranged entirelyoutside of the screens so that these members do not interfere withremoving and replacing the doctor assemblies. The doctor assembly can bereadily removed through one of the sleeves connected to the screenwhereupon the screen can be replaced in a quick and efficient manner.

Since a number of successive screens are employed, it is important toprovide a means for adjusting their positions relatively to one anotherso that the prints of the successive stencils correctly overlap oneanother on the material to be printed. The adjustment for varying therotational or angular relationship between gears 10 and 1] of the geartrain previously described enables rotational adjustment of the screensso as to provide the proper overlap.

FIG. 1 discloses a construction wherein each of the screens is drivenfrom only one end thereof and wherein the driven ends of adjacentscreens are at opposite ends of the machine. On the other hand, it isalso possible to provide a construction wherein all of the driven endsof the screens may be disposed at one side of the machine and all of thefreely rotatable ends of the screens may be disposed at the oppositeside of the machine.

Referring now to FIG. 5, a modified form of the invention is illustratedwherein two groups A and B of cylindrical screens 3 are provided and aresupported by bearing means 2 disposed on a frame 1. A web 35 is fed fromone end of the machine to the other in the direction of arrow P by aconventional feeder mechanism 36. The web passes from the printingmachine into a treatment installation 37 and a collector 38.

Bearing means 2 includes a first plurality of bearing assemblies 4 whichare driven bearing assemblies and second bearing assemblies 5 which arefreely rotatable or non-driven.

The two groups of screens A and B are offset with respect to one anothertransversely of the direction of travel of the web, the freely rotatablebearing assemblies 5 of the two groups being situated in a central areaof the path of web 35 to that the inner ends of the screens of the twogroups of screens are substantially in longitudinal alignment withrespect to the direction of travel of the web. With this construction,the screens are adapted to print over a width of a web which is twicethe length of an individual screen.

Referring now to FIG. 7, a top view is schematically illustrated of aweb 35 having a pattern printed thereon by means of a machine asconstructed in accordance with FIGS. 1-4 inclusive and employing asingle group of aligned screens. FIG. 6 is a top view schematicallyillustrating a web 35 having a pattern printed thereon by means of amachine as constructed in accordance with FIG. 5 employing two groups ofscreens which are offset with respect to one another transversely of thedirection of travel of the web. It is apparent that when utilizing thesame size screens, the arrangement shown in FIG. 6 enables the printingof a desired pattern of twice the width of the pattern printed with theconstruction shown in FIG. 7 and accordingly a web may be printed onwith the construction shown in FIG. 7.

It will be understood that this invention is susceptible to modificationin order to adapt it to different usages and conditions, andaccordingly, it is desired to comprehend such modifications within thisinvention as may fall within the scope of the appended claims.

What is claimed is:

I. A rotating screen printing machine comprising a frame, means on saidframe for supporting a web to be printed while advancing from one end ofthe machine to the other, a cylindrical seamless perforated screen of athin, flexible material extending transversely of the direction oftravel of the web, a rigid hollow sleeve connected to each of theopposite ends of said screen, a pair of spaced aligned bearingassemblies on said frame supporting said sleeves and said screen forrotation so that the screen bears in continuous printing relation uponthe web during printing, a doctor blade within said screen and bearingagainst the inner side of the associated screen in opposed relationshipto the web, means for introducing printing liquid within said screenbehind the associated doctor blade with respect to the direction ofmovement of the screen past the blade, means for positively androtatably driving a said sleeve at only one end of said screen while thesleeve at the opposite end of the screen is freely rotatably supported,and means for maintaining said screen under tension axially thereofwhile being driven whereby the sleeve at the said opposite end of saidscreen is rotated by a positive driving torque transmitted through thescreen.

2. A printing machine as claimed in claim 1 wherein said machinecomprises a plurality of said screens each positioned transversely ofthe direction of travel of said web.

3. A printing machine as claimed in claim 2, and means for adjusting theposition of the non-driven bearing assembly of each screen bothtransversely and longitudinally of the direction of travel of the web.

4. A printing machine as claimed in claim 2, wherein said adjustingmeans includes first means for shifting each pair of bearing assembliestogether with the associated screen transversely of the direction oftravel of the web, and second means for shifting only that hearingassembly associated with the non-driven end of each screenlongitudinally of the direction of travel of the web.

5. A printing machine as claimed in claim 2 including a plurality ofgroups of screens, the driven sleeve associated with each screen of afirst group of screens being disposed at one side of said frame and thedriven sleeve of each screen of a second group of screens being disposedat the opposite side of said frame.

6. A printing machine as claimed in claim 5 wherein said first andsecond groups of screens are offset with respect to one anothertransversely of the direction of travel of the web.

7. A printing machine as claimed in claim 6 including rotatable supportmeans, the non-driven ends of said screens being journaled in saidrotatable support means and being disposed substantially in longitudinalalignment with respect to the direction of travel of the web, thescreens of said two groups extending in opposite directions with respectto each other from the non-driven ends thereof.

8. A printing machine as claimed in claim 2, wherein said means formaintaining said screens under tension comprising at least two rodsextending between each pair of bearing assemblies, the rods between eachpair of bearing assemblies being disposed adjacent diametricallyopposite portions of the associated screen, each end of said rods beingsecured to one of the associated bearing assemblies, and spring meansfor resiliently acting between each rod and the other of the associatedbearing assemblies, one of the rods associated with each pair of bearingassemblies being interconnected with said frame.

9. A printing machine as claimed in claim 8, wherein the interconnectionof each one of said rods with said frame comprises a threaded membermounted for rotation by the frame and held against axial movement withrespect thereto, each of said rods being threaded into one of saidthreaded members.

10. A printing machine as claimed in claim 8, wherein said spring meansincludes a member slidably supported on the associated rod, a movablecam face engageable with said rod and a resilient member disposedbetween said slidable member and the adjacent bearing assembly.

11. A printing machine as claimed in claim 10, wherein said spring meansincludes a member which is a supporting block having an eccentric borereceiving said rod and which is rotatably mounted in said frame.

12. A printing machine as claimed in claim 2 including an elongatedsupporting member supporting said doctor blade within each screen, eachsupporting member having the opposite ends thereof projecting beyond thecorresponding ends of the associated screen and sleeves, and supportstructure means for supporting the opposite ends of said supportingmember.

13. A printing machine as claimed in claim 12, wherein said supportingmember includes a tapered finder nose at one end thereof, said supportstructure means having an upwardly slanting supporting face cooperatingwith said finder nose when the doctor blade is inserted in invertedposition, and fastening means engaging the opposite end of saidsupporting member to hold the supporting member in operative position.

14. A printing machine as claimed in claim 2 and comprising a supportingmember for each of said doctor blades, said each one doctor blade andsaid supporting member therefor define a doctor blade assembly, saiddoctor blade assembly being supported independently of the associatedscreen and said sleeves having a dimension such that said doctor bladeassembly can be mounted and dismounted endwise through said sleeves.

15. In a rotating screen printing machine comprising a frame, means onsaid frame for supporting a web to be printed while advancing from oneend of the machine to the other, a cylindrical seamless perforatedscreen of a thin flexible material extending transversely of thedirection of travel of the web, relatively rigid hollow sleevesconnected to opposite ends of said screen, a pair of spaced alignedbearing assemblies on said frame supporting said sleeves and said screenfor rotation so that the screen bears in continuous printing relationupon the web during printing, means for positively and rotatably drivingone of said sleeves at only one end of said screen while the sleeve atthe opposite end of the screen is freely rotatably supported, and meansfor maintaining said screen under tension axially semblies.

I! l IF i UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENTND; I 3 892 176 DATED 1 July 1, 1975 |NVENTOR(S) Johannes Bernardus ander Winden It is certified that error appears in tire abeve-ideritifiedpatent and that said Letters Patent are hereby corrected as shown beiow:

(73) Assignee: Stork-Amsterdam N.V.

Amstelveen, the Netherlands Signed and Sealed this sixteenth Day OfMarch 1976 [SEAL] Arrest.

RUTH C. MASON C. MARSHALL DANN AHPSIl'Hg ffi ('ummissr'mu-r I'Patenrsand Trademarks

1. A rotating screen printing machine comprising a frame, means on saidframe for supporting a web to be printed while advancing from one end ofthe machine to the other, a cylindrical seamless perforated screen of athin, flexible material extending transversely of the direction oftravel of the web, a rigid hollow sleeve connected to each of theopposite ends of said screen, a pair of spaced aligned bearingassemblies on said frame supporting said sleeves and said screen forrotation so that the screen bears in continuous printing relation uponthe web during printing, a doctor blade within said screen and bearingagainst the inner side of the associated screen in opposed relationshipto the web, means for introducing printing liquid within said screenbehinD the associated doctor blade with respect to the direction ofmovement of the screen past the blade, means for positively androtatably driving a said sleeve at only one end of said screen while thesleeve at the opposite end of the screen is freely rotatably supported,and means for maintaining said screen under tension axially thereofwhile being driven whereby the sleeve at the said opposite end of saidscreen is rotated by a positive driving torque transmitted through thescreen.
 2. A printing machine as claimed in claim 1 wherein said machinecomprises a plurality of said screens each positioned transversely ofthe direction of travel of said web.
 3. A printing machine as claimed inclaim 2, and means for adjusting the position of the non-driven bearingassembly of each screen both transversely and longitudinally of thedirection of travel of the web.
 4. A printing machine as claimed inclaim 2, wherein said adjusting means includes first means for shiftingeach pair of bearing assemblies together with the associated screentransversely of the direction of travel of the web, and second means forshifting only that bearing assembly associated with the non-driven endof each screen longitudinally of the direction of travel of the web. 5.A printing machine as claimed in claim 2 including a plurality of groupsof screens, the driven sleeve associated with each screen of a firstgroup of screens being disposed at one side of said frame and the drivensleeve of each screen of a second group of screens being disposed at theopposite side of said frame.
 6. A printing machine as claimed in claim 5wherein said first and second groups of screens are offset with respectto one another transversely of the direction of travel of the web.
 7. Aprinting machine as claimed in claim 6 including rotatable supportmeans, the non-driven ends of said screens being journaled in saidrotatable support means and being disposed substantially in longitudinalalignment with respect to the direction of travel of the web, thescreens of said two groups extending in opposite directions with respectto each other from the non-driven ends thereof.
 8. A printing machine asclaimed in claim 2, wherein said means for maintaining said screensunder tension comprising at least two rods extending between each pairof bearing assemblies, the rods between each pair of bearing assembliesbeing disposed adjacent diametrically opposite portions of theassociated screen, each end of said rods being secured to one of theassociated bearing assemblies, and spring means for resiliently actingbetween each rod and the other of the associated bearing assemblies, oneof the rods associated with each pair of bearing assemblies beinginterconnected with said frame.
 9. A printing machine as claimed inclaim 8, wherein the interconnection of each one of said rods with saidframe comprises a threaded member mounted for rotation by the frame andheld against axial movement with respect thereto, each of said rodsbeing threaded into one of said threaded members.
 10. A printing machineas claimed in claim 8, wherein said spring means includes a memberslidably supported on the associated rod, a movable cam face engageablewith said rod and a resilient member disposed between said slidablemember and the adjacent bearing assembly.
 11. A printing machine asclaimed in claim 10, wherein said spring means includes a member whichis a supporting block having an eccentric bore receiving said rod andwhich is rotatably mounted in said frame.
 12. A printing machine asclaimed in claim 2 including an elongated supporting member supportingsaid doctor blade within each screen, each supporting member having theopposite ends thereof projecting beyond the corresponding ends of theassociated screen and sleeves, and support structure means forsupporting the opposite ends of said supporting member.
 13. A printingmachine as claimed in claim 12, wherein said supporting member includesa taPered finder nose at one end thereof, said support structure meanshaving an upwardly slanting supporting face cooperating with said findernose when the doctor blade is inserted in inverted position, andfastening means engaging the opposite end of said supporting member tohold the supporting member in operative position.
 14. A printing machineas claimed in claim 2 and comprising a supporting member for each ofsaid doctor blades, said each one doctor blade and said supportingmember therefor define a doctor blade assembly, said doctor bladeassembly being supported independently of the associated screen and saidsleeves having a dimension such that said doctor blade assembly can bemounted and dismounted endwise through said sleeves.
 15. In a rotatingscreen printing machine comprising a frame, means on said frame forsupporting a web to be printed while advancing from one end of themachine to the other, a cylindrical seamless perforated screen of a thinflexible material extending transversely of the direction of travel ofthe web, relatively rigid hollow sleeves connected to opposite ends ofsaid screen, a pair of spaced aligned bearing assemblies on said framesupporting said sleeves and said screen for rotation so that the screenbears in continuous printing relation upon the web during printing,means for positively and rotatably driving one of said sleeves at onlyone end of said screen while the sleeve at the opposite end of thescreen is freely rotatably supported, and means for maintaining saidscreen under tension axially thereof while being driven whereby thesleeve at the said opposite end of the screen is rotated by a positivedriving torque transmitted through the screen.
 16. In a printing machineas claimed in claim 15 and said tension maintaining means comprising arod between said pair of bearing assemblies and one end of said rodbeing secured to one of the bearing assemblies, and spring means forresiliently acting between the other end of said rod and the other ofthe bearing assemblies.